Crocodyliformes

Fossilised skeleton and reconstruction of Protosuchus richardsoni, photographed by Ryan Somma.

Belongs within: Crocodylomorpha.
Contains: Metasuchia.

The Crocodyliformes correspond to the 'Crocodylia' of many earlier authors (with the latter generally now restricted to the crown group of crocodilians). The basalmost forms, the protosuchians, were still relatively lightly built taxa, though undeniably crocodile-like. Members of the basal lineage including modern species, the Mesoeucrocodylia, are united by the fusion of the frontal bones of the skull, together with the development of a secondary palate from the posterior extension of the palatine bones.

Synapomorphies (from Benton & Clark 1988): Otoccipital contacting ventromedial part of quadrate, enclosing carotid artery and forming passage for cranial nerves IX-XI; basisphenoid rostrum dorsoventrally expanded; basipterygoid process reduced, basipterygoid joint closed suturally; pterygoid extending dorsally, forming ventrolateral edge of trigeminal foramen; otoccipitals broadly meeting dorsal to foramen magnum; eustachian tubes enclosed between basioccipital and basisphenoid; antorbital fenestra much smaller than orbit; premaxilla and maxilla sutured together along butt joint; parietal lacking broad occipital portion; ventromedial end of coracoid anteroposteriorly expanded, anterior edge concave; quadrate hollow with several fenestrae on dorsal surface; mastoid antrum extending through supraoccipital; two large palpebrals present; dorsal head of quadrate contacting laterosphenoid; skull table in temporal region with nearly flat dorsal surface; postorbital medial to jugal on postorbital bar; scapula dramatically broadening dorsally.

Crocodyliformes [Crocodilia]
    |--Protosuchia SL01
    |    |--Orthosuchus stormbergi GPS06
    |    `--Protosuchidae [Stegomosuchidae] GPS06
    |         |  i. s.: Notochampsa R72
    |         |         Erythrochampsa R72
    |         |         Stegomosuchus R72
    |         |         Platyognathus R72
    |         |         Microchampsa R72
    |         |--Edentosuchus tienshanensis GPS06
    |         `--+--Hemiprotosuchus leali GPS06
    |            `--Protosuchus Brown 1934 GPS06, D07 (see below for synonymy)
    |                 |--P. haughtoni D07
    |                 |--P. micmac D07
    |                 `--P. richardsoni GPS06
    `--Mesoeucrocodylia [Mesosuchia] SL01
         |  i. s.: Brachychampsa Gilmore 1911 D07
         |           |--B. montana SF03
         |           `--B. sealeyi D07
         |--+--Zaraasuchus shepardi GPS06
         |  `--Gobiosuchus [Gobiosuchidae] GPS06
         |       `--G. kielanae GPS06
         `--+--+--Hsisosuchus chungkingensis GPS06
            |  `--Metasuchia GPS06
            `--+--Zosuchus davidsoni GPS06
               `--+--Shantungosuchus hangjinensis GPS06
                  `--Sichuanosuchus shuhanensis GPS06

Crocodyliformes incertae sedis:
  Mekosuchinae D07
    |--Mekosuchus inexpectatus WH02
    `--Quinkana Molnar 1961 D07
         |--Q. babarra D07
         |--Q. fortirostrum D07
         |--Q. meboldi D07
         `--Q. timera D07
  Trematochampsidae RRO00
    |--Trematochampsa taqueti Buffetaut 1974 LB02
    |--Eremosuchus elkoholicus RRO00
    |--Hamadasuchus rebouli RRO00
    `--Amargasuchus minor RRO00
  Crocidileimus robustus Gervais 1873 LB02
  Diplocynodus C77
    |--D. sphenops Cope 1875 C77
    `--D. subulatus C77
  Allodaposuchus precedens Nopcsa 1928 PST99
  Dolichochampsa minima SF03
  Aigialosuchus Persson 1959 LS04
  Pristichampsus rollinatii RRO00
  Asiatosuchus depressifrons RRO00

Protosuchus GPS06 [incl. Archaeosuchus R72, Baroqueosuchus Busbey & Gow 1984 BC88, Lesothosuchus Whetstone & Whybrow 1983 BC88]

*Type species of generic name indicated

REFERENCES

[BC88] Benton, M. J., & J. M. Clark. 1988. Archosaur phylogeny and the relationships of the Crocodylia. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 295–338. Clarendon Press: Oxford.

[C77] Cope, E. D. 1877. Report upon the extinct Vertebrata obtained in New Mexico by parties of the expedition of 1874. Geographical Surveys West of the One Hundredth Meridian 4 (2): i–iv, 1–370.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[GPS06] Gasparini, Z., D. Pol & L. A. Spalletti. 2006. An unusual marine crocodyliform from the Jurassic–Cretaceous boundary of Patagonia. Science 311: 70–73.

[LB02] Lapparent de Broin, F. de. 2002. Elosuchus, a new genus of crocodile from the Lower Cretaceous of the north of Africa. Comptes Rendus Palevol 1: 275–285.

[LS04] Lindgren, J., & M. Siverson. 2004. The first record of the mosasaur Clidastes from Europe and its palaeogeographical implications. Acta Palaeontologica Polonica 49 (2): 219–234.

[PST99] Pereda Suberbiola, X., & P. Taquet. 1999. Restes de Rhabdodon (dinosaure ornithopode) de Transylvanie donnés par Nopcsa au Muséum national d'Histoire naturelle de Paris. Geodiversitas 21 (2): 157–166.

[R72] Romer, A. S. 1972. The Chañares (Argentina) Triassic reptile fauna. XVI. Thecodont classification. Breviora 395: 1–24.

[RRO00] Rossmann, T., M. Rauhe & F. Ortega. 2000. Studies on Cenozoic crocodiles: 8. Bergisuchus dietrichbergi Kuhn (Sebecosuchia: Bergisuchidae n. fam.) from the Middle Eocene of Germany, some new systematic and biological conclusions. Paläontologische Zeitschrift 74: 379–392.

[SF03] Salisbury, S. W., E. Frey, D. M. Martill & M. C. Buchy. 2003. A new crocodilian from the Lower Cretaceous Crato Formatioin of north-eastern Brazil. Palaeontographica Abteilung A: Paläozoologie—Stratigraphie 270: 3–47.

[SL01] Sereno, P. C., H. C. E. Larsson, C. A. Sidor & B. Gado. 2001. The giant crocodyliform Sarcosuchus from the Cretaceous of Africa. Science 294: 1516–1519.

[WH02] Worthy, T. H., & R. N. Holdaway. 2002. The Lost World of the Moa: Prehistoric life of New Zealand. Indiana University Press: Bloomington (Indiana).

Last updated: 3 August 2017.